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Published for SISSA by Springer

Received: June 13, 2011

Accepted: July 16, 2011

Published: August 1, 2011

Search for same-sign top-quark pair production at√
s = 7 TeV and limits on flavour changing neutral

currents in the top sector

The CMS collaboration

Abstract: An inclusive search for same-sign top-quark pair production in pp collisions
at
√
s = 7 TeV is performed using a data sample recorded with the CMS detector in 2010,

corresponding to an integrated luminosity of 35 pb−1. This analysis is motivated by recent
studies of pp → tt reporting mass-dependent forward-backward asymmetries larger than
expected from the standard model. These asymmetries could be due to Flavor Changing
Neutral Currents (FCNC) in the top sector induced by t-channel exchange of a massive
neutral vector boson (Z′). Models with such a Z′ also predict enhancement of same-sign
top-pair production in pp or pp collisions. Limits are set as a function of the Z′ mass and
its couplings to u and t quarks. These limits disfavour the FCNC interpretation of the
Tevatron results.

Keywords: Hadron-Hadron Scattering

ArXiv ePrint: 1106.2142

Open Access, Copyright CERN,

for the benefit of the CMS Collaboration

doi:10.1007/JHEP08(2011)005

http://arxiv.org/abs/1106.2142
http://dx.doi.org/10.1007/JHEP08(2011)005


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u

ū

t

t̄

Z ′

Figure 1. Diagram for tt production induced by t-channel Z′ exchange, which can generate a
forward-backward asymmetry.

The Compact Muon Solenoid (CMS) Collaboration recently published a search for new
physics in events with same-sign isolated dileptons, jets, and E/T [1]. The results of that
search are recast in this short Letter to set constraints on the production of same-sign
top-quark pairs at the Large Hadron Collider (LHC). This effort is motivated by the recent
Tevatron measurements of the forward-backward tt asymmetry (AFB) which deviates from
the standard model (SM) expectations [2–4]. Many of the attempts put forth [5–25] to
explain this asymmetry invoke Flavour Changing Neutral Currents (FCNC) in the top-
quark sector [5] mediated by the t-channel exchange of a new massive Z′ boson, as shown
in figure 1. It has also been suggested [19, 22–25] that the anomalous dijet invariant mass
distribution recently reported by the CDF collaboration in pp→W + 2 jets [26] could be
evidence for such a boson.

The same type of interaction would also give rise to same-sign top-quark pair pro-
duction, as illustrated in figure 2. In this case, the initial state involves two u quarks.
Because of the large valence quark parton density of the proton, the tt production cross
section at the Large Hadron Collider (LHC) could then be large enough to be observable
with a modest amount of integrated luminosity. This motivates the search described in
this Letter.

For concreteness, we consider the model of ref. [10]. The relevant u-t-Z′ interaction
term in the Lagrangian is

L = gWuγµ(fLPL + fRPR)tZ′µ + h.c., (1)

where gW is the weak coupling strength, and PL and PR are the left-handed and right-
handed projection operators. The left-handed coupling is set to fL = 0, because of the
Bd-Bd mixing constraint [27]. The right-handed coupling fR and the Z′ mass (MZ′) are
the free parameters of the model. Within this model there is a narrow range of parameter
space consistent with the Tevatron measurements of σ(pp → tt) and AFB, which is not
excluded by direct searches for same-sign top-quark pairs [10].

We search for pp→ tt or pp→ ttj using a data sample corresponding to an integrated
luminosity of 35 pb−1, collected at a centre-of-mass energy of 7 TeV in 2010 by the CMS
experiment [28] at the LHC. We concentrate on the final state where both top quarks decay
as t→Wb followed by W→ `ν, where ` = e or µ. Thus, the final state of interest contains

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u

u

t

t

Z ′ Z ′

t

t

u

u

u

g

t

Z ′ t

ū

g

u

t

Z ′ t

ū

Figure 2. Diagrams for tt and ttj production in the presence of a Z′.

two high transverse momentum (pT ) isolated positive leptons (e+ or µ+), two or more jets,
and missing transverse energy (E/T ) from two neutrinos.

The result presented here is based on an already published search for new physics in
events with same-sign isolated dileptons, jets, and E/T [1]. In that search we presented event
yields and background expectations for a number of event selections sensitive to different
possible new physics contributions. We observed no excess of events for any of the event
selections, and we established 95% confidence level (CL) upper limits on non-standard
model event yields.

We now reinterpret the results of ref. [1] in terms of the model of eq. (1). We start
from the “baseline event selection” defined in [1]. Briefly, this selection consisted of two
same-sign isolated leptons of pT > 10 GeV, one of which must have pT > 20 GeV, at least
two jets of pT > 30 GeV and E/T > 20 (30) GeV for eµ (µµ or ee). Leptons and jets were
reconstructed in the pseudorapidity ranges |η| < 2.4 and |η| < 2.5, respectively. Three
events passed these requirements, with an expected background of 3.4± 1.8.

For the purpose of the tt search, the baseline event selection is modified by raising the
transverse momentum threshold on the lowest pT lepton from 10 to 20 GeV, since leptons
from t→Wb, W→ `ν tend to have high pT . In addition, we demand that both leptons be
positive since we are searching for pp → tt and not pp → tt. These changes are expected
to reduce the background by more than a factor of two.

These requirements select 2 events, while the background expectation is 0.9 ± 0.6
events. The main background contribution is attributed to tt events with one lepton from
W decay and one “fake” lepton, i.e. a lepton from heavy flavour decay, an electron from
unidentified photon conversion, or a muon from meson decays in flight and other processes.
This background is estimated in a data-driven way from studies of the sample of events
selected with looser lepton isolation and identification requirements. More details on the
event selection and the background estimation can be found in ref. [1].

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Source ee µµ eµ all
Lepton selection 11.8% 10.6% 10.8% 10.7%
Energy scale 8% 8% 8% 8%
ISR/FSR and PDF 3% 3% 3% 3%
Total without luminosity 14.6% 13.6% 13.8 13.7%
Integrated luminosity 4% 4% 4% 4%
Total 15% 14% 14% 14%

Table 1. Fractional systematic uncertainties on the pp→ tt(j) signal selection efficiency. ISR/FSR
denote initial and final state radiation.

As a cross-check, we repeat the analysis with the same kinematic selection, but requir-
ing the two leptons to be negative. No events in the data satisfy these requirements, in
agreement with the charge-symmetric background expectation of 0.9± 0.6 events.

There is no statistically significant excess of tt candidate events over the background
prediction. We thus proceed to set limits on the parameters of the Lagrangian of eq. (1).
The ingredients for this calculation are the observed (2) and expected (0.9± 0.6) number
of events, the cross section for pp→tt(j) as a function of fR and MZ′ , the efficiency of the
event selection, the integrated luminosity, and all associated uncertainties.

We used the external model interface in the MadGraph [29] event generator to cal-
culate at the leading order (LO) the tt + ttj cross section as a function of fR and MZ′ . In
this calculation we used the CTEQ6L [30] parton distribution functions (PDFs), fixed the
top quark mass Mtop to be 172.5 GeV, and set the renormalization and factorization scales
to be µ = Mtop.

MadGraph was also used to generate pp→tt and pp→ttj events according to the dia-
grams of figure 2. These events were then processed by Pythia [31] for parton showering,
followed by the CMS parametrized event simulation, and the same chain of reconstruction
and analysis programs used for collision data. The event selection efficiency, including
all relevant branching ratios, is (0.95 ± 0.13)%, independent of Z′ mass. Note that the
branching ratio for tt→ `νb`νb (` = e, µ) is 4.54% [32], but our selection is also sensitive
to leptons from tau decays. The fractional systematic uncertainty on the event selection
efficiencies was calculated as in ref. [1], and its components are summarized in table 1.

We compute the upper limits using a Bayesian method [32]. We assume a flat prior
for the signal strength and a log-normal distribution for the nuisance parameters. The
95% CL upper limit on the number of signal events is 5.7 using a 14% uncertainty on the
signal efficiency (table 1). The expected upper limit is 4.4+1.4

−1.3 events. The limit on the cross
section is σ(pp→ tt(j)) < 17.0 pb at 95% CL. As a cross-check, we also calculate the upper
limit on the number of events using the hybrid frequentist-Bayesian CLs approach [33].
With this method we find an upper limit of 5.6 events, which demonstrates the insensitivity
of our results to the details of the statistical analysis.

Using the LO cross section as computed in MadGraph, we turn the limit on the num-
ber of events into an exclusion region in the fR-MZ′ plane as shown in figure 3. The region
of parameter space consistent with the Tevatron AFB [10] is disfavoured by this analysis.

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 (GeV)Z'm
200 400 600 800 1000 1200 1400 1600 1800 2000

Rf

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

, Berger et al.
FB

 consistent with Aσ1

, Berger et al.
FB

 consistent with Aσ2

Combined Observed Limit tt + ttj

 = 7 TeVs, -1 = 35 pbintCMS  L

Figure 3. The shaded area is the exclusion region at 95% CL as a function of Z′ mass and right
handed couplings fR (see the Lagrangian of eq. (1)). We also show the region of parameter space
consistent with the Tevatron measurements of AFB and σ(tt) as inferred in ref. [10].

The Lagrangian of eq. (1) has two parameters, MZ′ and fR. At very large values of
MZ′ this lagrangian becomes equivalent to L = −1

2
CRR
Λ2 [uRγµtR][uRγµtR] + h.c. [34, 35],

with CRR
Λ2 = 2g2W f2

R

M2
Z′

. Using the fR limit calculated at MZ′ = 2 TeV, which is the highest

value of the Z′-mass considered in our analysis, we set a limit CRR
Λ2 < 2.7 TeV−2 at 95%

confidence level. This bound is more stringent than that recently reported by CDF: CRR
Λ2 <

3.7 TeV−2 [36].
In summary, we have established a limit on tt production in pp collisions at

√
s =

7 TeV, based on a search for same-sign dileptons. Our bound can be used to test models
of new physics with massive Z′ bosons that have been proposed to explain the Tevatron
measurements of the pp → tt forward-backward asymmetry. Our result disfavours this
FCNC interpretation.

Acknowledgments

We thank Johan Alwall, Ed Berger, Qing-Hong Cao, Chuan-Ren Chen, Chong-Sheng
Li and Hao Zhang for discussions and help in implementing the Z ′ model in Mad-

Graph/MadEvent. We wish to congratulate our colleagues in the CERN accelerator
departments for the excellent performance of the LHC machine. We thank the techni-
cal and administrative staff at CERN and other CMS institutes, and acknowledge sup-
port from: FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and
FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIEN-
CIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Es-

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tonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France);
BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE
and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF and WCU (Korea); LAS
(Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pak-
istan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine,
Uzbekistan); MST and MAE (Russia); MSTD (Serbia); MICINN and CPAN (Spain);
Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey);
STFC (United Kingdom); DOE and NSF (USA).

Open Access. This article is distributed under the terms of the Creative Commons
Attribution Noncommercial License which permits any noncommercial use, distribution,
and reproduction in any medium, provided the original author(s) and source are credited.

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http://www-spires.slac.stanford.edu/spires/find/hep/www?eprint=0706.2334
http://dx.doi.org/10.1088/1126-6708/2002/07/012
http://arxiv.org/abs/hep-ph/0201195
http://www-spires.slac.stanford.edu/spires/find/hep/www?eprint=HEP-PH/0201195
http://dx.doi.org/10.1088/1126-6708/2006/05/026
http://dx.doi.org/10.1088/1126-6708/2006/05/026
http://arxiv.org/abs/hep-ph/0603175
http://www-spires.slac.stanford.edu/spires/find/hep/www?eprint=HEP-PH/0603175
http://dx.doi.org/10.1088/0954-3899/37/7A/075021
http://dx.doi.org/10.1088/0954-3899/37/7A/075021
http://www-spires.slac.stanford.edu/spires/find/hep/www?j=JPHGB,G37,075021
http://cdsweb.cern.ch/record/451614
http://dx.doi.org/10.1016/j.physletb.2010.06.040
http://dx.doi.org/10.1016/j.physletb.2010.06.040
http://arxiv.org/abs/0912.1105
http://www-spires.slac.stanford.edu/spires/find/hep/www?eprint=0912.1105
http://dx.doi.org/10.1016/j.nuclphysb.2010.10.015
http://dx.doi.org/10.1016/j.nuclphysb.2010.10.015
http://arxiv.org/abs/1008.3562
http://www-spires.slac.stanford.edu/spires/find/hep/www?eprint=1008.3562
http://www-cdf.fnal.gov/physics/exotic/r2a/20110407.samesigndileptons/sstops.pdf


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The CMS collaboration

Yerevan Physics Institute, Yerevan, Armenia

S. Chatrchyan, V. Khachatryan, A.M. Sirunyan, A. Tumasyan

Institut für Hochenergiephysik der OeAW, Wien, Austria

W. Adam, T. Bergauer, M. Dragicevic, J. Erö, C. Fabjan, M. Friedl, R. Frühwirth,
V.M. Ghete, J. Hammer1, S. Hänsel, M. Hoch, N. Hörmann, J. Hrubec, M. Jeitler,
W. Kiesenhofer, M. Krammer, D. Liko, I. Mikulec, M. Pernicka, B. Rahbaran,
H. Rohringer, R. Schöfbeck, J. Strauss, A. Taurok, F. Teischinger, P. Wagner, W. Wal-
tenberger, G. Walzel, E. Widl, C.-E. Wulz

National Centre for Particle and High Energy Physics, Minsk, Belarus

V. Mossolov, N. Shumeiko, J. Suarez Gonzalez

Universiteit Antwerpen, Antwerpen, Belgium

S. Bansal, L. Benucci, E.A. De Wolf, X. Janssen, T. Maes, L. Mucibello, S. Ochesanu,
B. Roland, R. Rougny, M. Selvaggi, H. Van Haevermaet, P. Van Mechelen, N. Van Remortel

Vrije Universiteit Brussel, Brussel, Belgium

F. Blekman, S. Blyweert, J. D’Hondt, O. Devroede, R. Gonzalez Suarez, A. Kalogeropoulos,
M. Maes, W. Van Doninck, P. Van Mulders, G.P. Van Onsem, I. Villella

Université Libre de Bruxelles, Bruxelles, Belgium

O. Charaf, B. Clerbaux, G. De Lentdecker, V. Dero, A.P.R. Gay, G.H. Hammad, T. Hreus,
P.E. Marage, A. Raval, L. Thomas, C. Vander Velde, P. Vanlaer

Ghent University, Ghent, Belgium

V. Adler, A. Cimmino, S. Costantini, M. Grunewald, B. Klein, J. Lellouch, A. Marinov,
J. Mccartin, D. Ryckbosch, F. Thyssen, M. Tytgat, L. Vanelderen, P. Verwilligen, S. Walsh,
N. Zaganidis

Université Catholique de Louvain, Louvain-la-Neuve, Belgium

S. Basegmez, G. Bruno, J. Caudron, L. Ceard, E. Cortina Gil, J. De Favereau De Jeneret,
C. Delaere, D. Favart, A. Giammanco, G. Grégoire, J. Hollar, V. Lemaitre, J. Liao,
O. Militaru, C. Nuttens, S. Ovyn, D. Pagano, A. Pin, K. Piotrzkowski, N. Schul

Université de Mons, Mons, Belgium

N. Beliy, T. Caebergs, E. Daubie

Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro, Brazil

G.A. Alves, L. Brito, D. De Jesus Damiao, M.E. Pol, M.H.G. Souza

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Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil

W.L. Aldá Júnior, W. Carvalho, E.M. Da Costa, C. De Oliveira Martins, S. Fonseca De
Souza, L. Mundim, H. Nogima, V. Oguri, W.L. Prado Da Silva, A. Santoro, S.M. Silva Do
Amaral, A. Sznajder

Instituto de Fisica Teorica, Universidade Estadual Paulista, Sao Paulo, Brazil

C.A. Bernardes2, F.A. Dias, T.R. Fernandez Perez Tomei, E. M. Gregores2, C. Lagana,
F. Marinho, P.G. Mercadante2, S.F. Novaes, Sandra S. Padula

Institute for Nuclear Research and Nuclear Energy, Sofia, Bulgaria

N. Darmenov1, V. Genchev1, P. Iaydjiev1, S. Piperov, M. Rodozov, S. Stoykova, G. Sul-
tanov, V. Tcholakov, R. Trayanov

University of Sofia, Sofia, Bulgaria

A. Dimitrov, R. Hadjiiska, A. Karadzhinova, V. Kozhuharov, L. Litov, M. Mateev,
B. Pavlov, P. Petkov

Institute of High Energy Physics, Beijing, China

J.G. Bian, G.M. Chen, H.S. Chen, C.H. Jiang, D. Liang, S. Liang, X. Meng, J. Tao,
J. Wang, J. Wang, X. Wang, Z. Wang, H. Xiao, M. Xu, J. Zang, Z. Zhang

State Key Lab. of Nucl. Phys. and Tech., Peking University, Beijing, China

Y. Ban, S. Guo, Y. Guo, W. Li, Y. Mao, S.J. Qian, H. Teng, B. Zhu, W. Zou

Universidad de Los Andes, Bogota, Colombia

A. Cabrera, B. Gomez Moreno, A.A. Ocampo Rios, A.F. Osorio Oliveros, J.C. Sanabria

Technical University of Split, Split, Croatia

N. Godinovic, D. Lelas, K. Lelas, R. Plestina3, D. Polic, I. Puljak

University of Split, Split, Croatia

Z. Antunovic, M. Dzelalija

Institute Rudjer Boskovic, Zagreb, Croatia

V. Brigljevic, S. Duric, K. Kadija, S. Morovic

University of Cyprus, Nicosia, Cyprus

A. Attikis, M. Galanti, J. Mousa, C. Nicolaou, F. Ptochos, P.A. Razis

Charles University, Prague, Czech Republic

M. Finger, M. Finger Jr.

– 10 –



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Academy of Scientific Research and Technology of the Arab Republic of Egypt,
Egyptian Network of High Energy Physics, Cairo, Egypt

Y. Assran4, A. Ellithi Kamel, S. Khalil5, M.A. Mahmoud6

National Institute of Chemical Physics and Biophysics, Tallinn, Estonia

A. Hektor, M. Kadastik, M. Müntel, M. Raidal, L. Rebane, A. Tiko

Department of Physics, University of Helsinki, Helsinki, Finland

V. Azzolini, P. Eerola, G. Fedi

Helsinki Institute of Physics, Helsinki, Finland

S. Czellar, J. Härkönen, A. Heikkinen, V. Karimäki, R. Kinnunen, M.J. Kortelainen,
T. Lampén, K. Lassila-Perini, S. Lehti, T. Lindén, P. Luukka, T. Mäenpää, E. Tuominen,
J. Tuominiemi, E. Tuovinen, D. Ungaro, L. Wendland

Lappeenranta University of Technology, Lappeenranta, Finland

K. Banzuzi, A. Karjalainen, A. Korpela, T. Tuuva

Laboratoire d’Annecy-le-Vieux de Physique des Particules, IN2P3-CNRS,
Annecy-le-Vieux, France

D. Sillou

DSM/IRFU, CEA/Saclay, Gif-sur-Yvette, France

M. Besancon, S. Choudhury, M. Dejardin, D. Denegri, B. Fabbro, J.L. Faure, F. Ferri,
S. Ganjour, F.X. Gentit, A. Givernaud, P. Gras, G. Hamel de Monchenault, P. Jarry,
E. Locci, J. Malcles, M. Marionneau, L. Millischer, J. Rander, A. Rosowsky, I. Shreyber,
M. Titov, P. Verrecchia

Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau,
France

S. Baffioni, F. Beaudette, L. Benhabib, L. Bianchini, M. Bluj7, C. Broutin, P. Busson,
C. Charlot, T. Dahms, L. Dobrzynski, S. Elgammal, R. Granier de Cassagnac, M. Hague-
nauer, P. Miné, C. Mironov, C. Ochando, P. Paganini, D. Sabes, R. Salerno, Y. Sirois,
C. Thiebaux, B. Wyslouch8, A. Zabi

Institut Pluridisciplinaire Hubert Curien, Université de Strasbourg, Univer-
sité de Haute Alsace Mulhouse, CNRS/IN2P3, Strasbourg, France

J.-L. Agram9, J. Andrea, D. Bloch, D. Bodin, J.-M. Brom, M. Cardaci, E.C. Chabert,
C. Collard, E. Conte9, F. Drouhin9, C. Ferro, J.-C. Fontaine9, D. Gelé, U. Goerlach,
S. Greder, P. Juillot, M. Karim9, A.-C. Le Bihan, Y. Mikami, P. Van Hove

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Centre de Calcul de l’Institut National de Physique Nucleaire et de Physique
des Particules (IN2P3), Villeurbanne, France

F. Fassi, D. Mercier

Université de Lyon, Université Claude Bernard Lyon 1, CNRS-IN2P3, Institut
de Physique Nucléaire de Lyon, Villeurbanne, France

C. Baty, S. Beauceron, N. Beaupere, M. Bedjidian, O. Bondu, G. Boudoul, D. Boumediene,
H. Brun, J. Chasserat, R. Chierici, D. Contardo, P. Depasse, H. El Mamouni, J. Fay,
S. Gascon, B. Ille, T. Kurca, T. Le Grand, M. Lethuillier, L. Mirabito, S. Perries, V. Sordini,
S. Tosi, Y. Tschudi, P. Verdier

Institute of High Energy Physics and Informatization, Tbilisi State University,
Tbilisi, Georgia

D. Lomidze

RWTH Aachen University, I. Physikalisches Institut, Aachen, Germany

G. Anagnostou, S. Beranek, M. Edelhoff, L. Feld, N. Heracleous, O. Hindrichs, R. Jussen,
K. Klein, J. Merz, N. Mohr, A. Ostapchuk, A. Perieanu, F. Raupach, J. Sammet, S. Schael,
D. Sprenger, H. Weber, M. Weber, B. Wittmer

RWTH Aachen University, III. Physikalisches Institut A, Aachen, Germany

M. Ata, E. Dietz-Laursonn, M. Erdmann, T. Hebbeker, C. Heidemann, A. Hinzmann,
K. Hoepfner, T. Klimkovich, D. Klingebiel, P. Kreuzer, D. Lanske†, J. Lingemann,
C. Magass, M. Merschmeyer, A. Meyer, P. Papacz, H. Pieta, H. Reithler, S.A. Schmitz,
L. Sonnenschein, J. Steggemann, D. Teyssier

RWTH Aachen University, III. Physikalisches Institut B, Aachen, Germany

M. Bontenackels, M. Davids, M. Duda, G. Flügge, H. Geenen, M. Giffels, W. Haj Ahmad,
D. Heydhausen, F. Hoehle, B. Kargoll, T. Kress, Y. Kuessel, A. Linn, A. Nowack,
L. Perchalla, O. Pooth, J. Rennefeld, P. Sauerland, A. Stahl, M. Thomas, D. Tornier,
M.H. Zoeller

Deutsches Elektronen-Synchrotron, Hamburg, Germany

M. Aldaya Martin, W. Behrenhoff, U. Behrens, M. Bergholz10, A. Bethani, K. Borras,
A. Cakir, A. Campbell, E. Castro, D. Dammann, G. Eckerlin, D. Eckstein, A. Floss-
dorf, G. Flucke, A. Geiser, J. Hauk, H. Jung1, M. Kasemann, I. Katkov11, P. Katsas,
C. Kleinwort, H. Kluge, A. Knutsson, M. Krämer, D. Krücker, E. Kuznetsova, W. Lange,
W. Lohmann10, R. Mankel, M. Marienfeld, I.-A. Melzer-Pellmann, A.B. Meyer, J. Mnich,
A. Mussgiller, J. Olzem, A. Petrukhin, D. Pitzl, A. Raspereza, M. Rosin, R. Schmidt10,
T. Schoerner-Sadenius, N. Sen, A. Spiridonov, M. Stein, J. Tomaszewska, R. Walsh,
C. Wissing

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University of Hamburg, Hamburg, Germany

C. Autermann, V. Blobel, S. Bobrovskyi, J. Draeger, H. Enderle, U. Gebbert, M. Görner,
T. Hermanns, K. Kaschube, G. Kaussen, H. Kirschenmann, R. Klanner, J. Lange,
B. Mura, S. Naumann-Emme, F. Nowak, N. Pietsch, C. Sander, H. Schettler, P. Schleper,
E. Schlieckau, M. Schröder, T. Schum, H. Stadie, G. Steinbrück, J. Thomsen

Institut für Experimentelle Kernphysik, Karlsruhe, Germany

C. Barth, J. Bauer, J. Berger, V. Buege, T. Chwalek, W. De Boer, A. Dierlamm, G. Dirkes,
M. Feindt, J. Gruschke, C. Hackstein, F. Hartmann, M. Heinrich, H. Held, K.H. Hoffmann,
S. Honc, J.R. Komaragiri, T. Kuhr, D. Martschei, S. Mueller, Th. Müller, M. Niegel,
O. Oberst, A. Oehler, J. Ott, T. Peiffer, G. Quast, K. Rabbertz, F. Ratnikov, N. Ratnikova,
M. Renz, C. Saout, A. Scheurer, P. Schieferdecker, F.-P. Schilling, G. Schott, H.J. Simonis,
F.M. Stober, D. Troendle, J. Wagner-Kuhr, T. Weiler, M. Zeise, V. Zhukov11, E.B. Ziebarth

Institute of Nuclear Physics ”Demokritos”, Aghia Paraskevi, Greece

G. Daskalakis, T. Geralis, S. Kesisoglou, A. Kyriakis, D. Loukas, I. Manolakos, A. Markou,
C. Markou, C. Mavrommatis, E. Ntomari, E. Petrakou

University of Athens, Athens, Greece

L. Gouskos, T.J. Mertzimekis, A. Panagiotou, N. Saoulidou, E. Stiliaris

University of Ioánnina, Ioánnina, Greece

I. Evangelou, C. Foudas, P. Kokkas, N. Manthos, I. Papadopoulos, V. Patras, F.A. Triantis

KFKI Research Institute for Particle and Nuclear Physics, Budapest, Hungary

A. Aranyi, G. Bencze, L. Boldizsar, C. Hajdu1, P. Hidas, D. Horvath12, A. Kapusi,
K. Krajczar13, F. Sikler1, G.I. Veres13, G. Vesztergombi13

Institute of Nuclear Research ATOMKI, Debrecen, Hungary

N. Beni, J. Molnar, J. Palinkas, Z. Szillasi, V. Veszpremi

University of Debrecen, Debrecen, Hungary

P. Raics, Z.L. Trocsanyi, B. Ujvari

Panjab University, Chandigarh, India

S.B. Beri, V. Bhatnagar, N. Dhingra, R. Gupta, M. Jindal, M. Kaur, J.M. Kohli,
M.Z. Mehta, N. Nishu, L.K. Saini, A. Sharma, A.P. Singh, J. Singh, S.P. Singh

University of Delhi, Delhi, India

S. Ahuja, B.C. Choudhary, P. Gupta, S. Jain, A. Kumar, A. Kumar, M. Naimuddin,
K. Ranjan, R.K. Shivpuri

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Saha Institute of Nuclear Physics, Kolkata, India

S. Banerjee, S. Bhattacharya, S. Dutta, B. Gomber, S. Jain, R. Khurana, S. Sarkar

Bhabha Atomic Research Centre, Mumbai, India

R.K. Choudhury, D. Dutta, S. Kailas, V. Kumar, P. Mehta, A.K. Mohanty1, L.M. Pant,
P. Shukla

Tata Institute of Fundamental Research - EHEP, Mumbai, India

T. Aziz, M. Guchait14, A. Gurtu, M. Maity15, D. Majumder, G. Majumder, K. Mazumdar,
G.B. Mohanty, A. Saha, K. Sudhakar, N. Wickramage

Tata Institute of Fundamental Research - HECR, Mumbai, India

S. Banerjee, S. Dugad, N.K. Mondal

Institute for Research and Fundamental Sciences (IPM), Tehran, Iran

H. Arfaei, H. Bakhshiansohi16, S.M. Etesami, A. Fahim16, M. Hashemi, H. Hesari,
A. Jafari16, M. Khakzad, A. Mohammadi17, M. Mohammadi Najafabadi, S. Paktinat
Mehdiabadi, B. Safarzadeh, M. Zeinali18

INFN Sezione di Bari a, Università di Bari b, Politecnico di Bari c, Bari, Italy

M. Abbresciaa,b, L. Barbonea,b, C. Calabriaa,b, A. Colaleoa, D. Creanzaa,c, N. De
Filippisa,c,1, M. De Palmaa,b, L. Fiorea, G. Iasellia,c, L. Lusitoa,b, G. Maggia,c, M. Maggia,
N. Mannaa,b, B. Marangellia,b, S. Mya,c, S. Nuzzoa,b, N. Pacificoa,b, G.A. Pierroa,
A. Pompilia,b, G. Pugliesea,c, F. Romanoa,c, G. Rosellia,b, G. Selvaggia,b, L. Silvestrisa,
R. Trentaduea, S. Tupputia,b, G. Zitoa

INFN Sezione di Bologna a, Università di Bologna b, Bologna, Italy

G. Abbiendia, A.C. Benvenutia, D. Bonacorsia, S. Braibant-Giacomellia,b, L. Brigliadoria,
P. Capiluppia,b, A. Castroa,b, F.R. Cavalloa, M. Cuffiania,b, G.M. Dallavallea, F. Fabbria,
A. Fanfania,b, D. Fasanellaa, P. Giacomellia, M. Giuntaa, C. Grandia, S. Marcellinia,
G. Masettib, M. Meneghellia,b, A. Montanaria, F.L. Navarriaa,b, F. Odoricia, A. Perrottaa,
F. Primaveraa, A.M. Rossia,b, T. Rovellia,b, G. Sirolia,b, R. Travaglinia,b

INFN Sezione di Catania a, Università di Catania b, Catania, Italy

S. Albergoa,b, G. Cappelloa,b, M. Chiorbolia,b,1, S. Costaa,b, R. Potenzaa,b, A. Tricomia,b,
C. Tuvea,b

INFN Sezione di Firenze a, Università di Firenze b, Firenze, Italy

G. Barbaglia, V. Ciullia,b, C. Civininia, R. D’Alessandroa,b, E. Focardia,b, S. Frosalia,b,
E. Galloa, S. Gonzia,b, P. Lenzia,b, M. Meschinia, S. Paolettia, G. Sguazzonia,
A. Tropianoa,1

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INFN Laboratori Nazionali di Frascati, Frascati, Italy

L. Benussi, S. Bianco, S. Colafranceschi19, F. Fabbri, D. Piccolo

INFN Sezione di Genova, Genova, Italy

P. Fabbricatore, R. Musenich

INFN Sezione di Milano-Bicocca a, Università di Milano-Bicocca b, Milano,
Italy

A. Benagliaa,b, F. De Guioa,b,1, L. Di Matteoa,b, S. Gennai1, A. Ghezzia,b, S. Malvezzia,
A. Martellia,b, A. Massironia,b, D. Menascea, L. Moronia, M. Paganonia,b, D. Pedrinia,
S. Ragazzia,b, N. Redaellia, S. Salaa, T. Tabarelli de Fatisa,b

INFN Sezione di Napoli a, Università di Napoli ”Federico II” b, Napoli, Italy

S. Buontempoa, C.A. Carrillo Montoyaa,1, N. Cavalloa,20, A. De Cosaa,b, F. Fabozzia,20,
A.O.M. Iorioa,1, L. Listaa, M. Merolaa,b, P. Paoluccia

INFN Sezione di Padova a, Università di Padova b, Università di
Trento (Trento) c, Padova, Italy

P. Azzia, N. Bacchettaa, P. Bellana,b, D. Biselloa,b, A. Brancaa, R. Carlina,b, P. Checchiaa,
T. Dorigoa, U. Dossellia, F. Fanzagoa, F. Gasparinia,b, U. Gasparinia,b, A. Gozzelino,
S. Lacapraraa,21, I. Lazzizzeraa,c, M. Margonia,b, M. Mazzucatoa, A.T. Meneguzzoa,b,
M. Nespoloa,1, L. Perrozzia,1, N. Pozzobona,b, P. Ronchesea,b, F. Simonettoa,b, E. Torassaa,
M. Tosia,b, S. Vaninia,b, P. Zottoa,b, G. Zumerlea,b

INFN Sezione di Pavia a, Università di Pavia b, Pavia, Italy

P. Baessoa,b, U. Berzanoa, S.P. Rattia,b, C. Riccardia,b, P. Torrea,b, P. Vituloa,b,
C. Viviania,b

INFN Sezione di Perugia a, Università di Perugia b, Perugia, Italy

M. Biasinia,b, G.M. Bileia, B. Caponeria,b, L. Fanòa,b, P. Laricciaa,b, A. Lucaronia,b,1,
G. Mantovania,b, M. Menichellia, A. Nappia,b, F. Romeoa,b, A. Santocchiaa,b, S. Taronia,b,1,
M. Valdataa,b

INFN Sezione di Pisa a, Università di Pisa b, Scuola Normale Superiore di
Pisa c, Pisa, Italy

P. Azzurria,c, G. Bagliesia, J. Bernardinia,b, T. Boccalia,1, G. Broccoloa,c, R. Castaldia,
R.T. D’Agnoloa,c, R. Dell’Orsoa, F. Fioria,b, L. Foàa,c, A. Giassia, A. Kraana,
F. Ligabuea,c, T. Lomtadzea, L. Martinia,22, A. Messineoa,b, F. Pallaa, F. Palmonari,
G. Segneria, A.T. Serbana, P. Spagnoloa, R. Tenchinia, G. Tonellia,b,1, A. Venturia,1,
P.G. Verdinia

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INFN Sezione di Roma a, Università di Roma ”La Sapienza” b, Roma, Italy

L. Baronea,b, F. Cavallaria, D. Del Rea,b, E. Di Marcoa,b, M. Diemoza, D. Francia,b,
M. Grassia,1, E. Longoa,b, P. Meridiani, S. Nourbakhsha, G. Organtinia,b, F. Pandolfia,b,1,
R. Paramattia, S. Rahatloua,b, C. Rovelli1

INFN Sezione di Torino a, Università di Torino b, Università del Piemonte
Orientale (Novara) c, Torino, Italy

N. Amapanea,b, R. Arcidiaconoa,c, S. Argiroa,b, M. Arneodoa,c, C. Biinoa, C. Bottaa,b,1,
N. Cartigliaa, R. Castelloa,b, M. Costaa,b, N. Demariaa, A. Grazianoa,b,1, C. Mariottia,
M. Maronea,b, S. Masellia, E. Migliorea,b, G. Milaa,b, V. Monacoa,b, M. Musicha,b,
M.M. Obertinoa,c, N. Pastronea, M. Pelliccionia,b, A. Potenzaa,b, A. Romeroa,b,
M. Ruspaa,c, R. Sacchia,b, V. Solaa,b, A. Solanoa,b, A. Staianoa, A. Vilela Pereiraa

INFN Sezione di Trieste a, Università di Trieste b, Trieste, Italy

S. Belfortea, F. Cossuttia, G. Della Riccaa,b, B. Gobboa, D. Montaninoa,b, A. Penzoa

Kangwon National University, Chunchon, Korea

S.G. Heo, S.K. Nam

Kyungpook National University, Daegu, Korea

S. Chang, J. Chung, D.H. Kim, G.N. Kim, J.E. Kim, D.J. Kong, H. Park, S.R. Ro,
D.C. Son, T. Son

Chonnam National University, Institute for Universe and Elementary Particles,
Kwangju, Korea

Zero Kim, J.Y. Kim, S. Song

Korea University, Seoul, Korea

S. Choi, B. Hong, M. Jo, H. Kim, J.H. Kim, T.J. Kim, K.S. Lee, D.H. Moon, S.K. Park,
K.S. Sim

University of Seoul, Seoul, Korea

M. Choi, S. Kang, H. Kim, C. Park, I.C. Park, S. Park, G. Ryu

Sungkyunkwan University, Suwon, Korea

Y. Choi, Y.K. Choi, J. Goh, M.S. Kim, B. Lee, J. Lee, S. Lee, H. Seo, I. Yu

Vilnius University, Vilnius, Lithuania

M.J. Bilinskas, I. Grigelionis, M. Janulis, D. Martisiute, P. Petrov, T. Sabonis

Centro de Investigacion y de Estudios Avanzados del IPN, Mexico City, Mexico

H. Castilla-Valdez, E. De La Cruz-Burelo, I. Heredia-de La Cruz, R. Lopez-Fernandez,
R. Magaña Villalba, A. Sánchez-Hernández, L.M. Villasenor-Cendejas

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Universidad Iberoamericana, Mexico City, Mexico

S. Carrillo Moreno, F. Vazquez Valencia

Benemerita Universidad Autonoma de Puebla, Puebla, Mexico

H.A. Salazar Ibarguen

Universidad Autónoma de San Luis Potośı, San Luis Potośı, Mexico

E. Casimiro Linares, A. Morelos Pineda, M.A. Reyes-Santos

University of Auckland, Auckland, New Zealand

D. Krofcheck, J. Tam

University of Canterbury, Christchurch, New Zealand

P.H. Butler, R. Doesburg, H. Silverwood

National Centre for Physics, Quaid-I-Azam University, Islamabad, Pakistan

M. Ahmad, I. Ahmed, M.I. Asghar, H.R. Hoorani, W.A. Khan, T. Khurshid, S. Qazi

Institute of Experimental Physics, Faculty of Physics, University of Warsaw,
Warsaw, Poland

G. Brona, M. Cwiok, W. Dominik, K. Doroba, A. Kalinowski, M. Konecki, J. Krolikowski

Soltan Institute for Nuclear Studies, Warsaw, Poland

T. Frueboes, R. Gokieli, M. Górski, M. Kazana, K. Nawrocki, K. Romanowska-Rybinska,
M. Szleper, G. Wrochna, P. Zalewski

Laboratório de Instrumentação e F́ısica Experimental de Part́ıculas, Lisboa,
Portugal

N. Almeida, P. Bargassa, A. David, P. Faccioli, P.G. Ferreira Parracho, M. Gallinaro1,
P. Musella, A. Nayak, J. Pela1, P.Q. Ribeiro, J. Seixas, J. Varela

Joint Institute for Nuclear Research, Dubna, Russia

S. Afanasiev, I. Belotelov, I. Golutvin, A. Kamenev, V. Karjavin, G. Kozlov, A. Lanev,
P. Moisenz, V. Palichik, V. Perelygin, M. Savina, S. Shmatov, V. Smirnov, A. Volodko,
A. Zarubin

Petersburg Nuclear Physics Institute, Gatchina (St Petersburg), Russia

V. Golovtsov, Y. Ivanov, V. Kim, P. Levchenko, V. Murzin, V. Oreshkin, I. Smirnov,
V. Sulimov, L. Uvarov, S. Vavilov, A. Vorobyev, An. Vorobyev

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Institute for Nuclear Research, Moscow, Russia

Yu. Andreev, A. Dermenev, S. Gninenko, N. Golubev, M. Kirsanov, N. Krasnikov,
V. Matveev, A. Pashenkov, A. Toropin, S. Troitsky

Institute for Theoretical and Experimental Physics, Moscow, Russia

V. Epshteyn, V. Gavrilov, V. Kaftanov†, M. Kossov1, A. Krokhotin, N. Lychkovskaya,
V. Popov, G. Safronov, S. Semenov, V. Stolin, E. Vlasov, A. Zhokin

Moscow State University, Moscow, Russia

E. Boos, M. Dubinin23, L. Dudko, A. Ershov, A. Gribushin, O. Kodolova, I. Lokhtin,
A. Markina, S. Obraztsov, M. Perfilov, S. Petrushanko, L. Sarycheva, V. Savrin, A. Snigirev

P.N. Lebedev Physical Institute, Moscow, Russia

V. Andreev, M. Azarkin, I. Dremin, M. Kirakosyan, A. Leonidov, S.V. Rusakov, A. Vino-
gradov

State Research Center of Russian Federation, Institute for High Energy
Physics, Protvino, Russia

I. Azhgirey, I. Bayshev, S. Bitioukov, V. Grishin1, V. Kachanov, D. Konstantinov,
A. Korablev, V. Krychkine, V. Petrov, R. Ryutin, A. Sobol, L. Tourtchanovitch, S. Troshin,
N. Tyurin, A. Uzunian, A. Volkov

University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear
Sciences, Belgrade, Serbia

P. Adzic24, M. Djordjevic, D. Krpic24, J. Milosevic

Centro de Investigaciones Energéticas Medioambientales y Tec-
nológicas (CIEMAT), Madrid, Spain

M. Aguilar-Benitez, J. Alcaraz Maestre, P. Arce, C. Battilana, E. Calvo, M. Cepeda,
M. Cerrada, M. Chamizo Llatas, N. Colino, B. De La Cruz, A. Delgado Peris, C. Diez
Pardos, D. Domı́nguez Vázquez, C. Fernandez Bedoya, J.P. Fernández Ramos, A. Ferrando,
J. Flix, M.C. Fouz, P. Garcia-Abia, O. Gonzalez Lopez, S. Goy Lopez, J.M. Hernandez,
M.I. Josa, G. Merino, J. Puerta Pelayo, I. Redondo, L. Romero, J. Santaolalla, M.S. Soares,
C. Willmott

Universidad Autónoma de Madrid, Madrid, Spain

C. Albajar, G. Codispoti, J.F. de Trocóniz

Universidad de Oviedo, Oviedo, Spain

J. Cuevas, J. Fernandez Menendez, S. Folgueras, I. Gonzalez Caballero, L. Lloret Iglesias,
J.M. Vizan Garcia

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Instituto de F́ısica de Cantabria (IFCA), CSIC-Universidad de Cantabria,
Santander, Spain

J.A. Brochero Cifuentes, I.J. Cabrillo, A. Calderon, S.H. Chuang, J. Duarte Campderros,
M. Felcini25, M. Fernandez, G. Gomez, J. Gonzalez Sanchez, C. Jorda, P. Lobelle Pardo,
A. Lopez Virto, J. Marco, R. Marco, C. Martinez Rivero, F. Matorras, F.J. Munoz Sanchez,
J. Piedra Gomez26, T. Rodrigo, A.Y. Rodŕıguez-Marrero, A. Ruiz-Jimeno, L. Scodellaro,
M. Sobron Sanudo, I. Vila, R. Vilar Cortabitarte

CERN, European Organization for Nuclear Research, Geneva, Switzerland

D. Abbaneo, E. Auffray, G. Auzinger, P. Baillon, A.H. Ball, D. Barney, A.J. Bell27,
D. Benedetti, C. Bernet3, W. Bialas, P. Bloch, A. Bocci, S. Bolognesi, M. Bona, H. Breuker,
K. Bunkowski, T. Camporesi, G. Cerminara, T. Christiansen, J.A. Coarasa Perez, B. Curé,
D. D’Enterria, A. De Roeck, S. Di Guida, N. Dupont-Sagorin, A. Elliott-Peisert, B. Frisch,
W. Funk, A. Gaddi, G. Georgiou, H. Gerwig, D. Gigi, K. Gill, D. Giordano, F. Glege,
R. Gomez-Reino Garrido, M. Gouzevitch, P. Govoni, S. Gowdy, L. Guiducci, M. Hansen,
C. Hartl, J. Harvey, J. Hegeman, B. Hegner, H.F. Hoffmann, A. Honma, V. Innocente,
P. Janot, K. Kaadze, E. Karavakis, P. Lecoq, C. Lourenço, T. Mäki, M. Malberti,
L. Malgeri, M. Mannelli, L. Masetti, A. Maurisset, F. Meijers, S. Mersi, E. Meschi,
R. Moser, M.U. Mozer, M. Mulders, E. Nesvold1, M. Nguyen, T. Orimoto, L. Orsini,
E. Palencia Cortezon, E. Perez, A. Petrilli, A. Pfeiffer, M. Pierini, M. Pimiä, D. Piparo,
G. Polese, A. Racz, W. Reece, J. Rodrigues Antunes, G. Rolandi28, T. Rommerskirchen,
M. Rovere, H. Sakulin, C. Schäfer, C. Schwick, I. Segoni, A. Sharma, P. Siegrist, M. Simon,
P. Sphicas29, M. Spiropulu23, M. Stoye, P. Tropea, A. Tsirou, P. Vichoudis, M. Voutilainen,
W.D. Zeuner

Paul Scherrer Institut, Villigen, Switzerland

W. Bertl, K. Deiters, W. Erdmann, K. Gabathuler, R. Horisberger, Q. Ingram,
H.C. Kaestli, S. König, D. Kotlinski, U. Langenegger, F. Meier, D. Renker, T. Rohe,
J. Sibille30, A. Starodumov31

Institute for Particle Physics, ETH Zurich, Zurich, Switzerland

L. Bäni, P. Bortignon, L. Caminada32, B. Casal, N. Chanon, Z. Chen, S. Cittolin,
G. Dissertori, M. Dittmar, J. Eugster, K. Freudenreich, C. Grab, W. Hintz, P. Lecomte,
W. Lustermann, C. Marchica32, P. Martinez Ruiz del Arbol, P. Milenovic33, F. Moortgat,
C. Nägeli32, P. Nef, F. Nessi-Tedaldi, L. Pape, F. Pauss, T. Punz, A. Rizzi, F.J. Ronga,
M. Rossini, L. Sala, A.K. Sanchez, M.-C. Sawley, B. Stieger, L. Tauscher†, A. Thea,
K. Theofilatos, D. Treille, C. Urscheler, R. Wallny, M. Weber, L. Wehrli, J. Weng

Universität Zürich, Zurich, Switzerland

E. Aguilo, C. Amsler, V. Chiochia, S. De Visscher, C. Favaro, M. Ivova Rikova, B. Millan
Mejias, P. Otiougova, P. Robmann, A. Schmidt, H. Snoek

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National Central University, Chung-Li, Taiwan

Y.H. Chang, K.H. Chen, C.M. Kuo, S.W. Li, W. Lin, Z.K. Liu, Y.J. Lu, D. Mekterovic,
R. Volpe, J.H. Wu, S.S. Yu

National Taiwan University (NTU), Taipei, Taiwan

P. Bartalini, P. Chang, Y.H. Chang, Y.W. Chang, Y. Chao, K.F. Chen, W.-S. Hou,
Y. Hsiung, K.Y. Kao, Y.J. Lei, R.-S. Lu, J.G. Shiu, Y.M. Tzeng, M. Wang

Cukurova University, Adana, Turkey

A. Adiguzel, M.N. Bakirci34, S. Cerci35, C. Dozen, I. Dumanoglu, E. Eskut, S. Girgis,
G. Gokbulut, I. Hos, E.E. Kangal, A. Kayis Topaksu, G. Onengut, K. Ozdemir, S. Ozturk36,
A. Polatoz, K. Sogut37, D. Sunar Cerci35, B. Tali35, H. Topakli34, D. Uzun, L.N. Vergili,
M. Vergili

Middle East Technical University, Physics Department, Ankara, Turkey

I.V. Akin, T. Aliev, B. Bilin, S. Bilmis, M. Deniz, H. Gamsizkan, A.M. Guler, K. Ocalan,
A. Ozpineci, M. Serin, R. Sever, U.E. Surat, E. Yildirim, M. Zeyrek

Bogazici University, Istanbul, Turkey

M. Deliomeroglu, D. Demir38, E. Gülmez, B. Isildak, M. Kaya39, O. Kaya39, M. Özbek,
S. Ozkorucuklu40, N. Sonmez41

National Scientific Center, Kharkov Institute of Physics and Technology,
Kharkov, Ukraine

L. Levchuk

University of Bristol, Bristol, United Kingdom

F. Bostock, J.J. Brooke, T.L. Cheng, E. Clement, D. Cussans, R. Frazier, J. Goldstein,
M. Grimes, D. Hartley, G.P. Heath, H.F. Heath, L. Kreczko, S. Metson, D.M. Newbold42,
K. Nirunpong, A. Poll, S. Senkin, V.J. Smith

Rutherford Appleton Laboratory, Didcot, United Kingdom

L. Basso43, K.W. Bell, A. Belyaev43, C. Brew, R.M. Brown, B. Camanzi, D.J.A. Cockerill,
J.A. Coughlan, K. Harder, S. Harper, J. Jackson, B.W. Kennedy, E. Olaiya, D. Petyt,
B.C. Radburn-Smith, C.H. Shepherd-Themistocleous, I.R. Tomalin, W.J. Womersley,
S.D. Worm

Imperial College, London, United Kingdom

R. Bainbridge, G. Ball, J. Ballin, R. Beuselinck, O. Buchmuller, D. Colling, N. Cripps,
M. Cutajar, G. Davies, M. Della Negra, W. Ferguson, J. Fulcher, D. Futyan, A. Gilbert,
A. Guneratne Bryer, G. Hall, Z. Hatherell, J. Hays, G. Iles, M. Jarvis, G. Karapostoli,
L. Lyons, B.C. MacEvoy, A.-M. Magnan, J. Marrouche, B. Mathias, R. Nandi, J. Nash,

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A. Nikitenko31, A. Papageorgiou, M. Pesaresi, K. Petridis, M. Pioppi44, D.M. Raymond,
S. Rogerson, N. Rompotis, A. Rose, M.J. Ryan, C. Seez, P. Sharp, A. Sparrow, A. Tapper,
S. Tourneur, M. Vazquez Acosta, T. Virdee, S. Wakefield, N. Wardle, D. Wardrope,
T. Whyntie

Brunel University, Uxbridge, United Kingdom

M. Barrett, M. Chadwick, J.E. Cole, P.R. Hobson, A. Khan, P. Kyberd, D. Leslie,
W. Martin, I.D. Reid, L. Teodorescu

Baylor University, Waco, USA

K. Hatakeyama, H. Liu

The University of Alabama, Tuscaloosa, USA

C. Henderson

Boston University, Boston, USA

T. Bose, E. Carrera Jarrin, C. Fantasia, A. Heister, J. St. John, P. Lawson, D. Lazic,
J. Rohlf, D. Sperka, L. Sulak

Brown University, Providence, USA

A. Avetisyan, S. Bhattacharya, J.P. Chou, D. Cutts, A. Ferapontov, U. Heintz, S. Jabeen,
G. Kukartsev, G. Landsberg, M. Luk, M. Narain, D. Nguyen, M. Segala, T. Sinthuprasith,
T. Speer, K.V. Tsang

University of California, Davis, Davis, USA

R. Breedon, G. Breto, M. Calderon De La Barca Sanchez, S. Chauhan, M. Chertok,
J. Conway, P.T. Cox, J. Dolen, R. Erbacher, E. Friis, W. Ko, A. Kopecky, R. Lander,
H. Liu, S. Maruyama, T. Miceli, M. Nikolic, D. Pellett, J. Robles, S. Salur, T. Schwarz,
M. Searle, J. Smith, M. Squires, M. Tripathi, R. Vasquez Sierra, C. Veelken

University of California, Los Angeles, Los Angeles, USA

V. Andreev, K. Arisaka, D. Cline, R. Cousins, A. Deisher, J. Duris, S. Erhan, C. Farrell,
J. Hauser, M. Ignatenko, C. Jarvis, C. Plager, G. Rakness, P. Schlein†, J. Tucker, V. Valuev

University of California, Riverside, Riverside, USA

J. Babb, A. Chandra, R. Clare, J. Ellison, J.W. Gary, F. Giordano, G. Hanson, G.Y. Jeng,
S.C. Kao, F. Liu, H. Liu, O.R. Long, A. Luthra, H. Nguyen, B.C. Shen†, R. Stringer,
J. Sturdy, S. Sumowidagdo, R. Wilken, S. Wimpenny

University of California, San Diego, La Jolla, USA

W. Andrews, J.G. Branson, G.B. Cerati, D. Evans, F. Golf, A. Holzner, R. Kelley,
M. Lebourgeois, J. Letts, B. Mangano, S. Padhi, C. Palmer, G. Petrucciani, H. Pi, M. Pieri,
R. Ranieri, M. Sani, V. Sharma, S. Simon, E. Sudano, M. Tadel, Y. Tu, A. Vartak,
S. Wasserbaech45, F. Würthwein, A. Yagil, J. Yoo

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University of California, Santa Barbara, Santa Barbara, USA

D. Barge, R. Bellan, C. Campagnari, M. D’Alfonso, T. Danielson, K. Flowers, P. Geffert,
J. Incandela, C. Justus, P. Kalavase, S.A. Koay, D. Kovalskyi, V. Krutelyov, S. Lowette,
N. Mccoll, V. Pavlunin, F. Rebassoo, J. Ribnik, J. Richman, R. Rossin, D. Stuart, W. To,
J.R. Vlimant

California Institute of Technology, Pasadena, USA

A. Apresyan, A. Bornheim, J. Bunn, Y. Chen, M. Gataullin, Y. Ma, A. Mott, H.B. New-
man, C. Rogan, K. Shin, V. Timciuc, P. Traczyk, J. Veverka, R. Wilkinson, Y. Yang,
R.Y. Zhu

Carnegie Mellon University, Pittsburgh, USA

B. Akgun, R. Carroll, T. Ferguson, Y. Iiyama, D.W. Jang, S.Y. Jun, Y.F. Liu, M. Paulini,
J. Russ, H. Vogel, I. Vorobiev

University of Colorado at Boulder, Boulder, USA

J.P. Cumalat, M.E. Dinardo, B.R. Drell, C.J. Edelmaier, W.T. Ford, A. Gaz, B. Heyburn,
E. Luiggi Lopez, U. Nauenberg, J.G. Smith, K. Stenson, K.A. Ulmer, S.R. Wagner,
S.L. Zang

Cornell University, Ithaca, USA

L. Agostino, J. Alexander, A. Chatterjee, N. Eggert, L.K. Gibbons, B. Heltsley, K. Hen-
riksson, W. Hopkins, A. Khukhunaishvili, B. Kreis, G. Nicolas Kaufman, J.R. Patterson,
D. Puigh, A. Ryd, M. Saelim, E. Salvati, X. Shi, W. Sun, W.D. Teo, J. Thom, J. Thompson,
J. Vaughan, Y. Weng, L. Winstrom, P. Wittich

Fairfield University, Fairfield, USA

A. Biselli, G. Cirino, D. Winn

Fermi National Accelerator Laboratory, Batavia, USA

S. Abdullin, M. Albrow, J. Anderson, G. Apollinari, M. Atac, J.A. Bakken,
L.A.T. Bauerdick, A. Beretvas, J. Berryhill, P.C. Bhat, I. Bloch, F. Borcherding, K. Bur-
kett, J.N. Butler, V. Chetluru, H.W.K. Cheung, F. Chlebana, S. Cihangir, W. Cooper,
D.P. Eartly, V.D. Elvira, S. Esen, I. Fisk, J. Freeman, Y. Gao, E. Gottschalk, D. Green,
K. Gunthoti, O. Gutsche, J. Hanlon, R.M. Harris, J. Hirschauer, B. Hooberman, H. Jensen,
M. Johnson, U. Joshi, R. Khatiwada, B. Klima, K. Kousouris, S. Kunori, S. Kwan,
C. Leonidopoulos, P. Limon, D. Lincoln, R. Lipton, J. Lykken, K. Maeshima, J.M. Marraf-
fino, D. Mason, P. McBride, T. Miao, K. Mishra, S. Mrenna, Y. Musienko46, C. Newman-
Holmes, V. O’Dell, J. Pivarski, R. Pordes, O. Prokofyev, E. Sexton-Kennedy, S. Sharma,
W.J. Spalding, L. Spiegel, P. Tan, L. Taylor, S. Tkaczyk, L. Uplegger, E.W. Vaandering,
R. Vidal, J. Whitmore, W. Wu, F. Yang, F. Yumiceva, J.C. Yun

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University of Florida, Gainesville, USA

D. Acosta, P. Avery, D. Bourilkov, M. Chen, S. Das, M. De Gruttola, G.P. Di Giovanni,
D. Dobur, A. Drozdetskiy, R.D. Field, M. Fisher, Y. Fu, I.K. Furic, J. Gartner, J. Hugon,
B. Kim, J. Konigsberg, A. Korytov, A. Kropivnitskaya, T. Kypreos, J.F. Low, K. Matchev,
G. Mitselmakher, L. Muniz, C. Prescott, R. Remington, A. Rinkevicius, M. Schmitt,
B. Scurlock, P. Sellers, N. Skhirtladze, M. Snowball, D. Wang, J. Yelton, M. Zakaria

Florida International University, Miami, USA

V. Gaultney, L.M. Lebolo, S. Linn, P. Markowitz, G. Martinez, J.L. Rodriguez

Florida State University, Tallahassee, USA

T. Adams, A. Askew, J. Bochenek, J. Chen, B. Diamond, S.V. Gleyzer, J. Haas,
S. Hagopian, V. Hagopian, M. Jenkins, K.F. Johnson, H. Prosper, L. Quertenmont,
S. Sekmen, V. Veeraraghavan

Florida Institute of Technology, Melbourne, USA

M.M. Baarmand, B. Dorney, S. Guragain, M. Hohlmann, H. Kalakhety, I. Vodopiyanov

University of Illinois at Chicago (UIC), Chicago, USA

M.R. Adams, I.M. Anghel, L. Apanasevich, Y. Bai, V.E. Bazterra, R.R. Betts, J. Callner,
R. Cavanaugh, C. Dragoiu, L. Gauthier, C.E. Gerber, D.J. Hofman, S. Khalatyan,
G.J. Kunde47, F. Lacroix, M. Malek, C. O’Brien, C. Silkworth, C. Silvestre, A. Smoron,
D. Strom, N. Varelas

The University of Iowa, Iowa City, USA

U. Akgun, E.A. Albayrak, B. Bilki, W. Clarida, F. Duru, C.K. Lae, E. McCliment, J.-
P. Merlo, H. Mermerkaya48, A. Mestvirishvili, A. Moeller, J. Nachtman, C.R. Newsom,
E. Norbeck, J. Olson, Y. Onel, F. Ozok, S. Sen, J. Wetzel, T. Yetkin, K. Yi

Johns Hopkins University, Baltimore, USA

B.A. Barnett, B. Blumenfeld, A. Bonato, C. Eskew, D. Fehling, G. Giurgiu, A.V. Gritsan,
Z.J. Guo, G. Hu, P. Maksimovic, S. Rappoccio, M. Swartz, N.V. Tran, A. Whitbeck

The University of Kansas, Lawrence, USA

P. Baringer, A. Bean, G. Benelli, O. Grachov, R.P. Kenny Iii, M. Murray, D. Noonan,
S. Sanders, J.S. Wood, V. Zhukova

Kansas State University, Manhattan, USA

A.f. Barfuss, T. Bolton, I. Chakaberia, A. Ivanov, S. Khalil, M. Makouski, Y. Maravin,
S. Shrestha, I. Svintradze, Z. Wan

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Lawrence Livermore National Laboratory, Livermore, USA

J. Gronberg, D. Lange, D. Wright

University of Maryland, College Park, USA

A. Baden, M. Boutemeur, S.C. Eno, D. Ferencek, J.A. Gomez, N.J. Hadley, R.G. Kellogg,
M. Kirn, Y. Lu, A.C. Mignerey, K. Rossato, P. Rumerio, F. Santanastasio, A. Skuja,
J. Temple, M.B. Tonjes, S.C. Tonwar, E. Twedt

Massachusetts Institute of Technology, Cambridge, USA

B. Alver, G. Bauer, J. Bendavid, W. Busza, E. Butz, I.A. Cali, M. Chan, V. Dutta,
P. Everaerts, G. Gomez Ceballos, M. Goncharov, K.A. Hahn, P. Harris, Y. Kim, M. Klute,
Y.-J. Lee, W. Li, C. Loizides, P.D. Luckey, T. Ma, S. Nahn, C. Paus, D. Ralph, C. Roland,
G. Roland, M. Rudolph, G.S.F. Stephans, F. Stöckli, K. Sumorok, K. Sung, D. Velicanu,
E.A. Wenger, R. Wolf, S. Xie, M. Yang, Y. Yilmaz, A.S. Yoon, M. Zanetti

University of Minnesota, Minneapolis, USA

S.I. Cooper, P. Cushman, B. Dahmes, A. De Benedetti, P.R. Dudero, G. Franzoni,
A. Gude, J. Haupt, K. Klapoetke, Y. Kubota, J. Mans, N. Pastika, V. Rekovic, R. Rusack,
M. Sasseville, A. Singovsky, N. Tambe

University of Mississippi, University, USA

L.M. Cremaldi, R. Godang, R. Kroeger, L. Perera, R. Rahmat, D.A. Sanders, D. Summers

University of Nebraska-Lincoln, Lincoln, USA

K. Bloom, S. Bose, J. Butt, D.R. Claes, A. Dominguez, M. Eads, P. Jindal, J. Keller,
T. Kelly, I. Kravchenko, J. Lazo-Flores, H. Malbouisson, S. Malik, G.R. Snow

State University of New York at Buffalo, Buffalo, USA

U. Baur, A. Godshalk, I. Iashvili, S. Jain, A. Kharchilava, A. Kumar, S.P. Shipkowski,
K. Smith

Northeastern University, Boston, USA

G. Alverson, E. Barberis, D. Baumgartel, O. Boeriu, M. Chasco, S. Reucroft, J. Swain,
D. Trocino, D. Wood, J. Zhang

Northwestern University, Evanston, USA

A. Anastassov, A. Kubik, N. Odell, R.A. Ofierzynski, B. Pollack, A. Pozdnyakov,
M. Schmitt, S. Stoynev, M. Velasco, S. Won

University of Notre Dame, Notre Dame, USA

L. Antonelli, D. Berry, A. Brinkerhoff, M. Hildreth, C. Jessop, D.J. Karmgard, J. Kolb,
T. Kolberg, K. Lannon, W. Luo, S. Lynch, N. Marinelli, D.M. Morse, T. Pearson, R. Ruchti,
J. Slaunwhite, N. Valls, M. Wayne, J. Ziegler

– 24 –



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The Ohio State University, Columbus, USA

B. Bylsma, L.S. Durkin, J. Gu, C. Hill, P. Killewald, K. Kotov, T.Y. Ling, M. Rodenburg,
C. Vuosalo, G. Williams

Princeton University, Princeton, USA

N. Adam, E. Berry, P. Elmer, D. Gerbaudo, V. Halyo, P. Hebda, A. Hunt, J. Jones,
E. Laird, D. Lopes Pegna, D. Marlow, T. Medvedeva, M. Mooney, J. Olsen, P. Piroué,
X. Quan, B. Safdi, H. Saka, D. Stickland, C. Tully, J.S. Werner, A. Zuranski

University of Puerto Rico, Mayaguez, USA

J.G. Acosta, X.T. Huang, A. Lopez, H. Mendez, S. Oliveros, J.E. Ramirez Vargas,
A. Zatserklyaniy

Purdue University, West Lafayette, USA

E. Alagoz, V.E. Barnes, G. Bolla, L. Borrello, D. Bortoletto, M. De Mattia, A. Everett,
A.F. Garfinkel, L. Gutay, Z. Hu, M. Jones, O. Koybasi, M. Kress, A.T. Laasanen,
N. Leonardo, C. Liu, V. Maroussov, P. Merkel, D.H. Miller, N. Neumeister, I. Shipsey,
D. Silvers, A. Svyatkovskiy, H.D. Yoo, J. Zablocki, Y. Zheng

Purdue University Calumet, Hammond, USA

N. Parashar

Rice University, Houston, USA

A. Adair, C. Boulahouache, K.M. Ecklund, F.J.M. Geurts, B.P. Padley, R. Redjimi,
J. Roberts, J. Zabel

University of Rochester, Rochester, USA

B. Betchart, A. Bodek, Y.S. Chung, R. Covarelli, P. de Barbaro, R. Demina, Y. Eshaq,
H. Flacher, A. Garcia-Bellido, P. Goldenzweig, Y. Gotra, J. Han, A. Harel, D.C. Miner,
D. Orbaker, G. Petrillo, W. Sakumoto, D. Vishnevskiy, M. Zielinski

The Rockefeller University, New York, USA

A. Bhatti, R. Ciesielski, L. Demortier, K. Goulianos, G. Lungu, S. Malik, C. Mesropian

Rutgers, the State University of New Jersey, Piscataway, USA

O. Atramentov, A. Barker, D. Duggan, Y. Gershtein, R. Gray, E. Halkiadakis, D. Hidas,
D. Hits, A. Lath, S. Panwalkar, R. Patel, K. Rose, S. Schnetzer, S. Somalwar, R. Stone,
S. Thomas

University of Tennessee, Knoxville, USA

G. Cerizza, M. Hollingsworth, S. Spanier, Z.C. Yang, A. York

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Texas A&M University, College Station, USA

R. Eusebi, W. Flanagan, J. Gilmore, A. Gurrola, T. Kamon, V. Khotilovich, R. Montalvo,
I. Osipenkov, Y. Pakhotin, A. Safonov, S. Sengupta, A. Tatarinov, D. Toback, M. Wein-
berger

Texas Tech University, Lubbock, USA

N. Akchurin, C. Bardak, J. Damgov, C. Jeong, K. Kovitanggoon, S.W. Lee, T. Libeiro,
P. Mane, Y. Roh, A. Sill, I. Volobouev, R. Wigmans, E. Yazgan

Vanderbilt University, Nashville, USA

E. Appelt, E. Brownson, D. Engh, C. Florez, W. Gabella, M. Issah, W. Johns, P. Kurt,
C. Maguire, A. Melo, P. Sheldon, B. Snook, S. Tuo, J. Velkovska

University of Virginia, Charlottesville, USA

M.W. Arenton, M. Balazs, S. Boutle, B. Cox, B. Francis, J. Goodell, R. Hirosky,
A. Ledovskoy, C. Lin, C. Neu, R. Yohay

Wayne State University, Detroit, USA

S. Gollapinni, R. Harr, P.E. Karchin, P. Lamichhane, M. Mattson, C. Milstène, A. Sakharov

University of Wisconsin, Madison, USA

M. Anderson, M. Bachtis, J.N. Bellinger, D. Carlsmith, S. Dasu, J. Efron, L. Gray,
K.S. Grogg, M. Grothe, R. Hall-Wilton, M. Herndon, A. Hervé, P. Klabbers, J. Klukas,
A. Lanaro, C. Lazaridis, J. Leonard, R. Loveless, A. Mohapatra, I. Ojalvo, D. Reeder,
I. Ross, A. Savin, W.H. Smith, J. Swanson, M. Weinberg

†: Deceased
1: Also at CERN, European Organization for Nuclear Research, Geneva, Switzerland
2: Also at Universidade Federal do ABC, Santo Andre, Brazil
3: Also at Laboratoire Leprince-Ringuet, Ecole Polytechnique, IN2P3-CNRS, Palaiseau, France
4: Also at Suez Canal University, Suez, Egypt
5: Also at British University, Cairo, Egypt
6: Also at Fayoum University, El-Fayoum, Egypt
7: Also at Soltan Institute for Nuclear Studies, Warsaw, Poland
8: Also at Massachusetts Institute of Technology, Cambridge, USA
9: Also at Université de Haute-Alsace, Mulhouse, France

10: Also at Brandenburg University of Technology, Cottbus, Germany
11: Also at Moscow State University, Moscow, Russia
12: Also at Institute of Nuclear Research ATOMKI, Debrecen, Hungary
13: Also at Eötvös Loránd University, Budapest, Hungary
14: Also at Tata Institute of Fundamental Research - HECR, Mumbai, India
15: Also at University of Visva-Bharati, Santiniketan, India
16: Also at Sharif University of Technology, Tehran, Iran

– 26 –



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17: Also at Shiraz University, Shiraz, Iran
18: Also at Isfahan University of Technology, Isfahan, Iran
19: Also at Facoltà Ingegneria Università di Roma ”La Sapienza”, Roma, Italy
20: Also at Università della Basilicata, Potenza, Italy
21: Also at Laboratori Nazionali di Legnaro dell’ INFN, Legnaro, Italy
22: Also at Università degli studi di Siena, Siena, Italy
23: Also at California Institute of Technology, Pasadena, USA
24: Also at Faculty of Physics of University of Belgrade, Belgrade, Serbia
25: Also at University of California, Los Angeles, Los Angeles, USA
26: Also at University of Florida, Gainesville, USA
27: Also at Université de Genève, Geneva, Switzerland
28: Also at Scuola Normale e Sezione dell’ INFN, Pisa, Italy
29: Also at University of Athens, Athens, Greece
30: Also at The University of Kansas, Lawrence, USA
31: Also at Institute for Theoretical and Experimental Physics, Moscow, Russia
32: Also at Paul Scherrer Institut, Villigen, Switzerland
33: Also at University of Belgrade, Faculty of Physics and Vinca Institute of Nuclear Sciences,

Belgrade, Serbia
34: Also at Gaziosmanpasa University, Tokat, Turkey
35: Also at Adiyaman University, Adiyaman, Turkey
36: Also at The University of Iowa, Iowa City, USA
37: Also at Mersin University, Mersin, Turkey
38: Also at Izmir Institute of Technology, Izmir, Turkey
39: Also at Kafkas University, Kars, Turkey
40: Also at Suleyman Demirel University, Isparta, Turkey
41: Also at Ege University, Izmir, Turkey
42: Also at Rutherford Appleton Laboratory, Didcot, United Kingdom
43: Also at School of Physics and Astronomy, University of Southampton, Southampton, United

Kingdom
44: Also at INFN Sezione di Perugia; Università di Perugia, Perugia, Italy
45: Also at Utah Valley University, Orem, USA
46: Also at Institute for Nuclear Research, Moscow, Russia
47: Also at Los Alamos National Laboratory, Los Alamos, USA
48: Also at Erzincan University, Erzincan, Turkey

– 27 –


	The CMS collaboration